package com.study.zjh.ioswheeldemo.view;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

/**
 * 仿照IOS风格的选择器
 */
public class IosWheelView extends ScrollView {

        public static final String TAG = IosWheelView.class.getSimpleName();

        public static class OnWheelViewListener {
            public void onSelected(int selectedIndex, String item) {
            }
        }


        private Context context;

        private LinearLayout views;

        public IosWheelView(Context context) {
            super(context);
            init(context);
        }

        public IosWheelView(Context context, AttributeSet attrs) {
            super(context, attrs);
            init(context);
        }

        public IosWheelView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
            init(context);
        }

        //    String[] items;
        List<String> items;

        private List<String> getItems() {
            return items;
        }

        public void setItems(List<String> list) {
            if (null == items) {
                items = new ArrayList<String>();
            }
            items.clear();
            items.addAll(list);

            // 前面和后面补全
            for (int i = 0; i < offset; i++) {
                items.add(0, "");
                items.add("");
            }

            initData();

        }


        public static final int OFF_SET_DEFAULT = 1;
        int offset = OFF_SET_DEFAULT; // 偏移量（需要在最前面和最后面补全）

        public int getOffset() {
            return offset;
        }

        public void setOffset(int offset) {
            this.offset = offset;
        }

        int displayItemCount; // 每页显示的数量

        int selectedIndex = 1;


        private void init(Context context) {
            this.context = context;
            Log.d(TAG, "parent: " + this.getParent());
            this.setVerticalScrollBarEnabled(false);

            views = new LinearLayout(context);
            views.setOrientation(LinearLayout.VERTICAL);
            this.addView(views);

            scrollerTask = new Runnable() {

                public void run() {

                    int newY = getScrollY();
                    if (initialY - newY == 0) { // stopped
                        final int remainder = initialY % itemHeight;
                        final int divided = initialY / itemHeight;
                        if (remainder == 0) {
                            selectedIndex = divided + offset;

                            onSeletedCallBack();
                        } else {
                            if (remainder > itemHeight / 2) {
                                IosWheelView.this.post(new Runnable() {
                                    @Override
                                    public void run() {
                                        IosWheelView.this.smoothScrollTo(0, initialY - remainder + itemHeight);
                                        selectedIndex = divided + offset + 1;
                                        onSeletedCallBack();
                                    }
                                });
                            } else {
                                IosWheelView.this.post(new Runnable() {
                                    @Override
                                    public void run() {
                                        IosWheelView.this.smoothScrollTo(0, initialY - remainder);
                                        selectedIndex = divided + offset;
                                        onSeletedCallBack();
                                    }
                                });
                            }


                        }


                    } else {
                        initialY = getScrollY();
                        IosWheelView.this.postDelayed(scrollerTask, newCheck);
                    }
                }
            };


        }

        int initialY;

        Runnable scrollerTask;
        int newCheck = 50;

        public void startScrollerTask() {

            initialY = getScrollY();
            this.postDelayed(scrollerTask, newCheck);
        }

        private void initData() {
            displayItemCount = offset * 2 + 1;

            for (String item : items) {
                views.addView(createView(item));
            }

            refreshItemView(0);
        }

        int itemHeight = 0;
        /**
         * 这里可以设置字体的属性 大小啦,边距啦,什么东西都可以在这里设置;
         */
        private TextView createView(String item) {
            TextView tv = new TextView(context);
            tv.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
            tv.setSingleLine(true);
            // 设置字体大小为20sp
            tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 15);
            // 设置文字内容
            tv.setText(item);
            // 设置文字居中
            tv.setGravity(Gravity.CENTER);
            // 设置内边距
            int padding = dip2px(10);
            tv.setPadding(padding, padding, padding, padding);
            if (0 == itemHeight) {
                itemHeight = getViewMeasuredHeight(tv);
                Log.d(TAG, "itemHeight: " + itemHeight);
                views.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, itemHeight * displayItemCount));
                LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) this.getLayoutParams();
                this.setLayoutParams(new LinearLayout.LayoutParams(lp.width, itemHeight * displayItemCount));
            }
            return tv;
        }


        @Override
        protected void onScrollChanged(int l, int t, int oldl, int oldt) {
            super.onScrollChanged(l, t, oldl, oldt);

            refreshItemView(t);

            if (t > oldt) {
                Log.d(TAG, "向下滚动");
                scrollDirection = SCROLL_DIRECTION_DOWN;
            } else {
                Log.d(TAG, "向上滚动");
                scrollDirection = SCROLL_DIRECTION_UP;

            }


        }

        private void refreshItemView(int y) {
            int position = y / itemHeight + offset;
            int remainder = y % itemHeight;
            int divided = y / itemHeight;

            if (remainder == 0) {
                position = divided + offset;
            } else {
                if (remainder > itemHeight / 2) {
                    position = divided + offset + 1;
                }

            }

            int childSize = views.getChildCount();
            for (int i = 0; i < childSize; i++) {
                TextView itemView = (TextView) views.getChildAt(i);
                if (null == itemView) {
                    return;
                }
                if (position == i) {
                    itemView.setTextColor(Color.parseColor("#FF6A07"));
                } else {
                    itemView.setTextColor(Color.parseColor("#bbbbbb"));
                }
            }
        }

        /**
         * 获取选中区域的边界
         */
        int[] selectedAreaBorder;

        private int[] obtainSelectedAreaBorder() {
            if (null == selectedAreaBorder) {
                selectedAreaBorder = new int[2];
                selectedAreaBorder[0] = itemHeight * offset;
                selectedAreaBorder[1] = itemHeight * (offset + 1);
            }
            return selectedAreaBorder;
        }


        private int scrollDirection = -1;
        private static final int SCROLL_DIRECTION_UP = 0;
        private static final int SCROLL_DIRECTION_DOWN = 1;

        Paint paint;
        int viewWidth;

        @Override
        public void setBackgroundDrawable(Drawable background) {

            if (viewWidth == 0) {
                viewWidth = ((Activity) context).getWindowManager().getDefaultDisplay().getWidth();
                Log.d(TAG, "viewWidth: " + viewWidth);
            }

            if (null == paint) {
                paint = new Paint();
//                paint.setColor(Color.parseColor("#FF6A07"));
                paint.setColor(Color.parseColor("#00000000"));
                paint.setStrokeWidth(dip2px(1f));
            }

            background = new Drawable() {
                @Override
                public void draw(Canvas canvas) {
//                    canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[0], viewWidth * 5 / 6, obtainSelectedAreaBorder()[0], paint);
//                    canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[1], viewWidth * 5 / 6, obtainSelectedAreaBorder()[1], paint);
                    canvas.drawLine(0, obtainSelectedAreaBorder()[0], viewWidth, obtainSelectedAreaBorder()[0], paint);
                    canvas.drawLine(0, obtainSelectedAreaBorder()[1], viewWidth , obtainSelectedAreaBorder()[1], paint);
                }

                @Override
                public void setAlpha(int alpha) {

                }

                @Override
                public void setColorFilter(ColorFilter cf) {

                }

                @SuppressLint("WrongConstant")
                @Override
                public int getOpacity() {
                    return 0;
                }
            };


            super.setBackgroundDrawable(background);

        }

        @Override
        protected void onSizeChanged(int w, int h, int oldw, int oldh) {
            super.onSizeChanged(w, h, oldw, oldh);
            Log.d(TAG, "w: " + w + ", h: " + h + ", oldw: " + oldw + ", oldh: " + oldh);
            viewWidth = w;
            setBackgroundDrawable(null);
        }

        /**
         * 选中回调
         */
        private void onSeletedCallBack() {
            if (null != onWheelViewListener) {
                onWheelViewListener.onSelected(selectedIndex, items.get(selectedIndex));
            }

        }

        public void setSeletion(int position) {
            final int p = position;
            selectedIndex = p + offset;
            this.post(new Runnable() {
                @Override
                public void run() {
                    IosWheelView.this.smoothScrollTo(0, p * itemHeight);
                }
            });

        }

        public String getSeletedItem() {
            return items.get(selectedIndex);
        }

        public int getSeletedIndex() {
            return selectedIndex - offset;
        }


        @Override
        public void fling(int velocityY) {
            super.fling(velocityY / 3);
        }

        @Override
        public boolean onTouchEvent(MotionEvent ev) {
            if (ev.getAction() == MotionEvent.ACTION_UP) {

                startScrollerTask();
            }
            return super.onTouchEvent(ev);
        }

        private OnWheelViewListener onWheelViewListener;

        public OnWheelViewListener getOnWheelViewListener() {
            return onWheelViewListener;
        }

        public void setOnWheelViewListener(OnWheelViewListener onWheelViewListener) {
            this.onWheelViewListener = onWheelViewListener;
        }

        private int dip2px(float dpValue) {
            final float scale = context.getResources().getDisplayMetrics().density;
            return (int) (dpValue * scale + 0.5f);
        }

        private int getViewMeasuredHeight(View view) {
            int width = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
            int expandSpec = View.MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, View.MeasureSpec.AT_MOST);
            view.measure(width, expandSpec);
            return view.getMeasuredHeight();
        }
}
